[coreboot] [PATCH] x86.c and x86emu/YABEL updates
joe at settoplinux.org
Mon Oct 26 15:32:01 CET 2009
On Mon, 26 Oct 2009 12:53:27 +0100, Stefan Reinauer <stepan at coresystems.de>
> Peter Stuge wrote:
>> Stefan Reinauer wrote:
>>>>> - YABEL: copy back the IVT, BDA and VBIOS. Some Xorg drivers
>>>>> require this.
>>>> Which drivers?
>>> As you might imagine I did not test this on the majority of boards,
>>> so I can't give a full list of Xorg drivers with the problem,
>> Ah, no, of course not, but it would be great to just list the ones
>> you know about.
> Basically, what happens is that some drivers seem to do BIOS callbacks
> to set the display modes.
> On x86-64 the VGA option rom is executed in x86emu mode, so strictly
> speaking only a vga option rom is needed at 0xc0000.
> On x86(-32) systems vm86 is used by Xorg, and the card is (afaik) not
> (always) re-initialized, so in addition to that the IVT has to be
> intact. With seabios that is always the case, but with x86emu/yabel and
> FILO the copying is needed in order to be able to start X. Otherwise the
> X server will end itself after unsuccessfully attempting to set a mode.
> For the record, this happened to me on a i945 system with onboard
> graphics and a not-so-recent debian derivative. Things might be
> different with newer Xorgs and kernel mode setting, but I don't know for
> sure. Yet, assuming that the VGA option rom and IVT stays intact is
> probably fair on an x86 system.
Now that you mention it, this does sound familiar Stefan
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